TOPIC:

After reading all the posts about this mod I just had to do it, the risk of not doing it is way to high. I bought a used ZX cam chain tensioner and I didn't like that the pressure on the cam was much higher then the stock tensioner, even after I shortened the spring by 10mm, I decided to mod the stock one. Drilled a 4mm hole in the center, tapped it with 5mm. I've also countered the lock nut so that I can fit an O-Ring, I think it will provide a better seal. It's true that there is not much material for the thread but it seams to be fine, I will inspect it from time to time to see how it holds, if needed I will add a nut on the inside for more strength.

Nicely done. I like the minor mod on the flanged nut to accommodate an oring. You've obviously put some thought in to this. Kudos to you.

Nice Work!

After reading a few posts It might be smart to add more material to the back of the tensioner (or a nut on the inside) since it’s really thin back there, I would say I can see about three threads, question is, how much force dose this screw needs to hold if the tensioner fails. I have a friend that has a TIG welder so it’s somewhat easy to add a few mm to the back, then drill and tap again.
Thoughts ?

If is was me, I'd do exactly what Ronlander did, then I'd add a, say 1/4 inch thick (or whatever makes sense), round slug of aluminum with the appropriate diameter (i.e a thick washer), drilled and taped for the same size bolt, thread the bolt through the slug and into the tensioner body. Then wind wind the slug down tight on the tensioner body and tig weld the slug to the body using the bolt to keep everything in place.

Yep, I think that's what I'm going to do. will post some pictures once I have it completed.